A Virginia Tech researcher has found extremist groups are reaching more teens and young adults online.

According to James Hawdon, director of the Virginia Tech Center for Peace Studies and Violence Prevention, as of 2016, about 70 percent of Americans ages 15 to 21 have been exposed to extremist content online, a 20 percent increase since 2013.

Hawdon said he believes the Internet makes it easier to spread messages on social media, adding that the overall political and cultural climate may also be factor.

Many websites use algorithms to track what you click on and search online, providing a more personalized web experience, Hawdon said. For example, if you search for extremist content online, links related to those subjects are likely to show up on websites you visit, including your social media feeds.

“You are channeled in certain directions, and you need to be aware of that,” Hawdon said. “So I would encourage people to seek out opinions different than your own.”

Hawdon urges parents to talk to their kids about how these algorithms work on the Internet and how they’ll see links similar to ones they’ve clicked on before. He said he also believes it’s important for everyone to remember not to believe everything they read online.

Hawdon said he plans to expand his research to more countries to see if this trend is happening around the world.